Soild Oak T&G in new loft

[lxbn]

Have had a new loft built. The floor base is 18mm water resistant chipboard. I am going have a solid oak tongue & groove 18mm floor laid on the chipboard.
I have purchased the flooring (Elka) and read the installation instructions. There are two recommended methods of laying this floor. Nailing onto the wooden sub-floor or gluing ("traditional trowel method"?). The gluing is to the sub-floor not the T&G. Floating is specifically not recommended which is fine as the flooring is intended to be permanent.
I am keener on the gluing method as I really would like to avoid creaking and squeaking floors (the sub-floor squeaks in a couple of places but that should be fixed before the floor is laid) and gluing seems rigid and stable. Am I correct in my assumption and are there any drawbacks to the gluing method?

 

[WoodYouLike]

The adhesive will have hard time bonding with the water-resistant chipboard. (Nailing onto chipboard is not really recommended).

Use a flexible adhesive like MAPEI P990 and a correct notched trowel - not too fine - but allow for more bonding time.

 

[lxbn]

Thanks - and yes the instructions did mention that nailing to chipboard was not ideal as the nails may loosen over time.
For the bonding, would it help if the floor was coated with PVA or something like that before gluing down the floor?
Also what about the provision for expansion, is it the same ie leave a gap around the perimiter?

 

[WoodYouLike]

Not sure about the coating with PVAC, the 'reduced' ability of the water-resistant chipboard of bonding with the flexible adhesive would be reduced even more IMHO. You run the risk that the only connection between wood and subfloor would be your seal. But don't take my word for granted on this.

As for expansion: yes, no matter what installation method you use you have to leave at least 10mm expansion gap all around the floor. Rule of thumb: 4mm per meter width of the room: e.g 4 meter wide room makes 16mm gap.

 

[lxbn]

Thanks again. I was concerned about the adhesion, so I called the manufacturers and discussed it with the technical guy.

He has suggested that the best method, even better than gluing, is to use screws. The company has screws specifically designed for T&G and engineered woods floors with a small counter sunk head and special thread so pilot holes are not required. Apparently the screws will not work loose and will create a solid fix with the base and may even eliminate some existing small squeaks in the sub-floor. It is also a much cheaper option (about a tenth) than using their glue and removable if access to the underfloor is needed.

It sounds like a miracle option for me, and exactly what I need. Thanks for pointing out the adhesion problem which made me to go to the manufacturers.